Substrate frame

ABSTRACT

A substrate frame includes an insulative board ( 10   a ) having a pair of ear portions ( 13 ) extending along its longitudinal edges; a plurality of wiring substrate regions ( 11 ) arranged on the insulative board ( 10   a ) between the ear portions ( 13 ) at predetermined intervals; and a plurality of slits ( 15 ) provided between the wiring substrate regions so as to extend across the ear portions ( 13 ) or a plurality grooves ( 18 ) around the wiring substrate regions ( 11 ).

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a substrate frame for connecting toexternal terminals the electrodes of semiconductor chips mounted on thesubstrate frame and a method of making semiconductor devices using thesubstrate frame.

2. Description of the Related Art

Japanese patent application Kokai No. 11-87386 discloses such asemiconductor device as shown in FIGS. 2( a) and 2(b), wherein asemiconductor chip 2 is mounted on the first surface of a wiringsubstrate 1 with a conductive or insulative adhesive 3, with the circuitforming surface facing up. A plurality of pads or connecting electrodes1 a and their wirings (not shown) are formed on the first surface of thewiring substrate 1. The pads 1 a are exposed but the wirings and theother area are covered by a solder resist. A plurality of wires 4connect the pads 1 a and the pads 2 a of the semiconductor chip 2. Thesemiconductor chip 2, the adhesive 3, and the wires 4 are covered by aresin such as epoxy resin.

A plurality of pads and their wirings are formed on the second surfaceopposed to the first surface of the wiring substrate 1. Similarly to thefirst surface, the pads are exposed but the wirings and the other areaare covered by a solder resist. A plurality of external terminals orsolder balls 6 are joined to the pads on the second surface. It isunderstood that the wirings on the first and second surfaces areconnected via through-holes.

How to make such a semiconductor device will be described.

As shown in FIG. 2( c), a substrate frame 10 is prepared by bonding apair of copper foils on opposite surfaces of an insulating board andforming a row of wiring substrate regions 11 at predetermined intervalson each surface. On each wiring substrate, both the surfaces are etchedto form wiring patterns that include pads on the first and secondsurfaces of a wiring substrate 1 (FIG. 2( a)) and through holes providedat predetermined locations for connecting the wiring patterns on thefirst and second surfaces. A nickel-gold (NiAu) electrolytic plating isapplied to the interiors of the through holes for connecting the wiringpatters and to the pads for increasing the bonding property with thewires 4 and the solder balls 6. A solder resist is applied to the wiringpatterns and the other area but the pads.

A plurality of slits 12 are provided between the wiring substrateregions 11 and have a length less than that of the wiring substrateregions 11. A plurality of slits 14 are provided in the ear portions 13of the substrate frame 10 and have a length less that that of the wiringsubstrate regions 11. These slits 12 and 14 are formed by a routerprocess. A semiconductor chip 2 is bonded to a central mounting area 11a of the wiring substrate region 11 with a bond 3. Then, the pads 1 a ofthe wiring substrate region 11 and the pads 2 a of the semiconductorchip 2 are connected with wires 4. Then, the semiconductor chip 2, thebond 3, and the wires 4 within a package area 11 b are enclosed with aresinous mass 5. A plurality of solder balls 6 are joined to the pads onthe second surface of the wiring substrate region 11. Finally, the earportions at the four corners of the wiring substrate region 11 arepunched off to provide individual semiconductor devices.

However, the conventional semiconductor device suffers from thefollowing disadvantages.

A pair of lead patters are formed between the wiring substrate region 11and the ear portion 13 of the substrate frame 10 for electroplating thewiring pattern. The punching at the four corners of the wiring substrateregion 11 can damage the cut face, lowering the reliability. Thepunching may be replaced by cutting the four corners with a rotary saw.The saw cutting, however, requires cutting in the vertical and lateraldirections, lowering the productivity, especially, of large BGA.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the invention to provide a substrateframe having the improved productivity.

According to the invention there is provided a substrate frame includingan insulative board having a pair of ear portions extending along itslongitudinal edges; a plurality of wiring substrate regions arranged onthe insulative board between the ear portions at predeterminedintervals; and a plurality of slits provided between the wiringsubstrate regions and extending across the ear portions or groovesaround the wiring substrate regions.

The slits between the wiring substrate regions extend across the earportions of the substrate frame so that the individual semiconductordevices can be separated by cutting the ear portions in only onedirection or punching the grooves without any damage to the cut faces,thereby maximizing the productivity.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a substrate frame according to the firstembodiment of the invention;

FIG. 2( a) is a perspective view of a conventional semiconductor device;

FIG. 2( b) is a sectional view taken along line A—A of FIG. 2( a);

FIG. 2( c) is a plan view of a substrate frame for the semiconductordevice;

FIG. 3( a) is a plan view of a substrate frame according to the secondembodiment of the invention;

FIG. 3( b) is a sectional view taken along line B—B of FIG. 3( a).

DESCRIPTION OF THE PREFERRED EMBODIMENTS

First Embodiment

In FIG. 1, a substrate frame 10A is provided to replace the substrateframe 10 in FIG. 2( c). Similarly to the substrate frame 10, this frame10A is made by bonding a pair of copper foils to opposite surfaces of aninsulative board and forming a row of wiring substrate regions 11 atpredetermined intervals on each surface. The opposite surfaces of eachwiring substrate region 11 are etched to form wiring patterns thatinclude pads 1 a and 1 b on the first and second surfaces of the wiringsubstrate 1 and through-holes provided at predetermined locations forconnecting the wiring patterns on the first and second surfaces. Theinteriors of the through-holes are plated to connect the wiring patternsbut a nickel-gold electrolytic plating is applied to the pads 1 a and 1b to increase the bonding property with the wires and solder balls. Asolder resist is coated on the wiring patterns and the other area exceptfor the pads 1 a and 1 b.

A plurality of slits 15 are provided between the wiring substrateregions 11 of the substrate frame 10A and have a length greater thanthat of the wiring substrate regions 11, extending across the earportions 13 of the substrate frame 10A. Thus, the slits 15 separate theadjacent wiring substrate regions 11. These slits 15 are made by arouter process.

How to make semiconductor devices with the substrate frame 10A will bedescribed below.

A plurality of semiconductor chips 2 are bonded to the central mountingareas 11 a of wiring substrate regions 11 with a bond 3 (FIG. 2( a)).Then, the pads 1 a of a wiring substrate region 11 and the pads 2 a of asemiconductor chip 2 are connected with bonding wires 4. Then, thesemiconductor chip 2, the bond 3, and the wires 4 within a package area11 b are enclosed with a resinous mass 5. The solder balls 6 are joinedto the pads 1 b on the second surface of the wiring substrate region 11.Then, the ear portions 13 of the substrate frame 10A are cut off with arotary saw to provide individual semiconductor devices.

As has been described above, the wiring substrate regions 11 of thesubstrate frame 10A are separated completely by the slits 15. Thus, itis possible to provide individual semiconductor devices by cutting inonly one direction without damage to the cut surface.

Second Embodiment

In FIG. 3( a), a substrate frame 10B is used to replace the substrateframe 10 of FIG. 2( c). Similarly to the substrate frame 10, thissubstrate frame 10B is made by bonding a pair of copper foils toopposite surfaces of an insulative board 10 a to form a both sidedsubstrate and forming thereon a row of wiring substrate regions 11 atpredetermined intervals. The copper foils 10 b of the both sidedsubstrate are etched to form wiring patterns that include pads 1 a and 1b on the first and second surfaces of the wiring substrate 1 andthrough-holes at predetermined locations for connecting the wiringpatterns on the first and second surfaces. The interiors of thethrough-holes are plated to connect the wiring patterns electrically.

Then, a solder resist 10 c is coated over the wiring patterns and theother areas except for the pads 1 a and 1 b, to which a nickel-goldelectrolytic plating is applied to increase the bonding property withthe wire and the solder balls. A plurality of slits 17 are formedbetween the wiring substrate regions 11 by a router process to reducethe processing stress. A groove 18 is provided around each wiringsubstrate region 11 by removing the copper foil 10 b and the solderresist 10 c in a predetermined width.

How to make semiconductor devices with the substrate frame 10B will bedescribed below.

(1) A both sided substrate is prepared by bonding a pair of copper foils10 b to opposite surfaces of an insulative board 10 a. The copper foils10 c on the opposite sides are etched by the photolithographictechnology to form wiring patterns that include wiring substrate regions11 provided at predetermined intervals. The wiring patterns also includepads 1 a and 1 b, and lead patterns for. electrolytic plating.

(2) A plurality of through-holes are provided to connect the wiringpatterns on the opposite sides of the wiring substrate 1. A plurality ofholes 16 are provided in the ear portions 13 for transportation. Asolder resist 10 c is coated to the area other than the pads 1 a and 1 band the grooves 18, and a nickel-gold electrolytic plating is applied tothe pads 1 a and 1 b.

(3) The area other than the groove 18 is covered with an etching mask,and the wiring patter at the groove 18 (part of the lead pattern forelectrolytic plating) is removed by etching.

(4) The etching mask is removed, and slits 17 are formed between thewiring substrate regions 11 by the router process to complete thesubstrate frame 10B.

(5) A semiconductor chip 2 is bonded with a bond 3 to a central mountingarea 11 a of the wiring substrate region 11, and the pads 1 a of thewiring substrate region 11 and the pad 2 a of the semiconductor chip 2are connected with wires 4.

(6) The semiconductor chip 2, the bond 3, and the wires 4 within apackage area 11 b are enclosed with a resin 5. Solder balls 6 are joinedto the pads 1 b on the second surface of the wiring substrate region 11.

(7) The grooves 18 of the wiring substrate regions 11 are punched with ametal mold to provide individual semiconductor devices.

As has been described above, the substrate frame 10B has the grooves 18from which the wiring patterns have been removed so that individualsemiconductor devices are separated without any damage to the cutsurfaces merely by punching the grooves 18.

The substrate frame 10A or 10B may be applied to a multi-layer substratehaving three or more wiring layers. The wire bonding between the wiringsubstrate 1 and the semiconductor chip 2 may be replaced by the flipchip bonding.

1. A method of making semiconductor devices, comprising the steps of:providing an insulative board having a pair of ear portions extendingalong its longitudinal edges; arranging a plurality of wiring substrateregions on said insulative board between said ear portions atpredetermined intervals; mounting semiconductor chips on said wiringsubstrate regions; connecting pads of said wiring substrate regions andpads of said semiconductor chips; enclosing said semiconductor chipswith a resin; and cutting boundaries between said wiring substrateregions and said ear portions to provide individual semiconductordevices.
 2. A method of making semiconductor devices, comprising thesteps of: providing an insulative board having a pair of ear portionsextending along its longitudinal edges; a plurality of wiring substrateregions arranged on said insulative board between said ear portions atpredetermined intervals; providing a plurality of grooves around saidwiring substrate regions from which patterns are removed; mountingsemiconductor chips on said wiring substrate regions; connecting pads ofsaid wiring substrate regions and pads of said semiconductor chips;enclosing said semiconductor chips with a resin; and cutting saidgrooves with a mold punch to provide individual semiconductor devices.